Description: Sal uses the Pythagorean theorem to find the width of some carpet. Created by Sal Khan and Monterey Institute for Technology and Education. A carpet measures 7 feet long and has a diagonal measurement of square root of 74 feet. It has a length of 7 feet, so let's say that that is 7 feet, right there. So that means that this distance, the diagonal of the carpet, is the square root of 74 feet.*Teacher Advisor is 100% free.